Hello! Your puppy is beautiful. I have 3 Dutch Shepherds, all trained to a T to fit our lifestyle. When I got my first one, I really loved Leerburg.com and HIGHLY recommend. I never did order any of his training videos, but got so much out of his free articles. He has many detailed articles on training, as well as anything else related to the breed. I personally feel its really important to have both positive reinforcement and corrections(at the right time and stage in training) to teach the dog black and white what is expected- everyone has a different take on this but I feel Leerburgs approach is extremely balanced, fair and effective. I also think his theory of socialization and generalization is spot on (I.E- socialization doesn't necessarily mean letting every stranger and human being in the world pet your puppy). I also HIGHLY recommend a couple of books you can order from Amazon:
1) Schutzhund Obedience- Training in Drive by Sheila Booth and Gottfried Dildei
2) Top Working Dogs-A Schutzhund Training Manual by Deitmar Schellenberg.
Don't be deterred by the Schutzhund part if you don't intend to do Schutzund- these are all around excellent training books, as obedience is the first core of the Schutzhund sport. Both of these books teach you the principles of training and how to use your Dutch Shepherds incredible drive as the sole training tool. If I had to recommend just one for you, I would say the "Training in Drive" book by Sheila Booth, as it has a huge section dedicated to obedience(with general principles AND how-to teach each command) and also a large section detailing and explaining the different drives which each dog has a different God-given measure of. This will help you start to understand your dog as an individual to inform how you train him. However, the Top Working Dogs book has a ton of info on evaluating your dog (temperament evaluation, hard or soft, drives, instincts, strengths/weaknesses etc) as well. I feel so strongly about these books that if I had extra copies, I'd send them to you!
I think the more different sources you take the time to read and learn from, the more you'll educate yourself and formulate your own educated perspective on training, and what works for your dog's drive, personality, and for your unique goals. I also think its important to think critically. I have never learned from a source that I agreed with 150% all the time- even in these books, or with Leerburg. There are things I disagree with here and there- That doesn't mean you throw the baby out with the bathwater, and it also doesn't mean you commit blindly to a method with no exceptions. For example, in Sheila Booth's book, she emphasizes use of hoses (literally cut lengths of a garden hose) for training, instead of a stick since sticks can be dangerous. She's right, sticks can be dangerous which I have learned the hard way ($700 emergency vet visit from serious throat wound from fetching a stick)- but none of my dogs really respond to hoses and they never will. They like balls! Also, I tried her "two hose" game for building drive with one of my pups and it wasn't for him. I've also read the "holding the treat in your own mouth and then dropping it to the dog from your mouth" technique for teaching eye contact during healing. Nope- I don't do it that way. Training is a complex subject! Just read as much as you can while you have time. For starters, check out Leerburg.com and order those books! Wish you the best.
https://leerburg.com/articles-obedmarker.htm
https://leerburg.com/articles-puppytraining.htm